Does when you eat much impact weight loss as much as what you eat? Here's what you should know.

Carolyn Williams, Ph.D., R.D.; Reviewed by Jess Ball, M.S., R.D.
June 30, 2020
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There's more to weight loss than simply watching calories, which is why many diets focus on food quality or macronutrients. While this approach may help some people lose weight, the reality is that there's still a lot we don't know—particularly when it comes to the environmental and biological variables that facilitate (or hinder) weight-loss efforts.

One of those variables that's recently been of interest to researchers is the impact of meal timing. Over the past five years, several studies—all looking at weight loss, but each with a different focus and approach—have suggested similar findings: the time that you eat meals has a big impact on weight-loss success.

So, what are those optimal times to eat meals when trying to lose weight? There aren't exact times to share, since these would likely differ by individual, but there are some general recommendations for meal timing. Here's what research suggests is most effective for weight loss, starting with dinner and working back to the slightly more-controversial meal, breakfast.

Dinner

The overall consensus among health professionals and researchers is that it's best to eat dinner early (at least two to three hours before going to bed), and then close the kitchen for the night. This deters late-night snacking and allows the body to burn some calories off before bed. It also gives the body time for digestion, which allows for more restful sleep later. When you go to bed on a full stomach, you're less likely to get adequate, good-quality sleep which triggers hormonal changes that can deter weight loss.

There are two other reasons to dine early, though they aren't quite as obvious. First, new research suggests that our circadian rhythms enable the body to more efficiently burn calories, control blood glucose and optimize digestion earlier in the day. This means eating dinner at 5 p.m., as opposed to 8 p.m., could potentially impact weight loss by aligning closer to the body's internal clock. Second, an early dinner increases the block of time we go without food, which increases fat-burning and improves regulation of hormones that impact appetite, cravings and blood sugar.

Lunch

Recipe pictured above: Salmon Caesar Salad

The timing of lunch appears to have the least impact on weight loss, but what is notable about lunch is that it should be your biggest meal (along with breakfast if consumed). This goes back to those circadian rhythms driving the body's increased efficiency earlier in the day when it comes to digesting food, burning calories and regulating hormones.

And when we remember that food is fuel for our body, front-loading to get most of your required daily calories and nutrients in by early afternoon also makes sense from a practical, biological standpoint.

Breakfast

Recipe pictured above: Date & Pine Nut Overnight Oatmeal

Instead of asking what time to eat breakfast, the more popular question of late is: Should you eat breakfast if you're trying to lose weight?

While there's not a definitive answer, two things are clear: First, all of us technically "fast" each night while asleep, and almost everyone benefits from this fast. Healthy individuals should aim to go at least 12 hours between dinner and the next day's first meal for health benefits, including weight loss.

These two things can also play out several ways. For example, you can end dinner by 7 p.m. and then eat breakfast at 7 a.m. Or, if you're a fan of intermittent fasting or don't like to eat breakfast, you may end dinner by 7 p.m. and then eat your first meal after 11 a.m.

The takeaway is that you can successfully lose weight with both scenarios—being a regular breakfast eater or being an intermittent faster who skips breakfast. But there are two keys to this: The first is to make sure you get at least a 12-hour break between dinner and the next meal. The second is, regardless of whether you eat your first meal at 7 a.m. or 11 a.m., to make that first meal substantial and nutrient-dense.

The Bottom Line: When to Eat for Weight Loss

What does all of this really mean for weight loss when it comes to scheduling meals? From a professional standpoint, it suggests there's a lot more to learn about weight loss. But I also think that tweaking a few meal times and eating habits could have a pretty substantial impact on weight-loss pursuits and overall health. So if you're not sure where to start, here are a few ideas to try.

1.) Eat breakfast, but not necessarily in the morning. "Breakfast" technically refers to when you break your fast from the previous day, and there is no specific time that should occur as explained in above in the breakfast discussion. What's important is that when you break your fast, you fuel your body for the day with nutrient-rich foods (we love oatmeal or avocado toast with an egg.)

2.) Prioritize eating the first half of the day. Aim to consume the majority of your calories and nutrients by mid-afternoon. Also, remember there is no right or wrong way to do this. For one person, this may mean eating breakfast, lunch and two snacks. For another, it may mean eating a large brunch meal and one snack.

3.) Make dinner early and light. You may even consider eating as early as 4 or 5 p.m. ideal. If this isn't possible, then try to eat dinner at least three or more hours before bed.

4.) Go 12 hours between dinner and your next meal to reap benefits that facilitate weight loss, fat burning, metabolism and management of appetite and cravings. An easy way to achieve this is to push dinner a little earlier or skip the late-night snacks. Healthy individuals may consider going longer (13 to 16 hours) to reap even greater benefits in terms of fat-burning.

While often beneficial to the health of all individuals, those with a chronic health condition such as diabetes should consult with their health care provider, particularly if this is significantly different from their current eating times.

Carolyn Williams, PhD, RD, is author to the new cookbook, Meals That Heal: 100 Everyday Anti-Inflammatory Recipes in 30 Minutes or Less, and a culinary nutrition expert known for ability to simplify food and nutrition information. She received a 2017 James Beard Journalism award. You can follow her on Instagram @realfoodreallife_rd or on carolynwilliamsrd.com.